The present invention relates generally to antenna arrays for multi-beam antenna systems. In particular, the present invention relates to a cavity slot antenna array for a multi-beam antenna in a communications system.
It is common to use a single antenna array to provide a radiation pattern, or beam, which is steerable. For example, steerable beams are often produced by a planar or panel array of antenna elements each excited by a signal having a predetermined phase differential so as to produce a composite radiation pattern having a predefined shape and direction. In order to steer this composite beam, the phase differential between the antenna elements is adjusted to affect the composite radiation pattern.
A multiple beam antenna array may be created, utilizing a planar or panel array described above, for example, through the use of predetermined sets of phase differentials, where each set of phase differential defines a beam of the multiple beam antenna. For example, an array adapted to provide multiple selectable antenna beams, each of which is steered a different predetermined amount from the broadside, may be provided using a panel array and matrix type beam forming networks, such as a Butler or hybrid matrix. The afore referenced application entitled xe2x80x9cDual Mode Switched Beam Antennaxe2x80x9d describes an excellent scheme for providing such a multiple beam antenna system.
With such systems, it may be desirable to use antenna element arrays having antenna element columns with minimal inter spacing, such as inter-column spacing. Unfortunately, conventional antenna element arrays used in communications systems incorporate relatively bulky antenna elements (e.g., dipole elements) that each must be separately linked to a beam forming module. Such elements often consume excessive space, which makes it difficult to sufficiently reduce their spacing. In addition, with each element being separately linked to a beam forming module, excessive signal feed resources are required for supplying such linkage. Furthermore, it is tedious and costly to effectively mount each antenna element within the array chassis. For example, each element may have to be separately soldered to a grid chassis by a skilled technician. Thus, with conventional communication system antenna element arrays, it is difficult to implement multiple beam system methodologies.
Accordingly, what is needed in the art is an improved antenna element array for a multi-beam antenna in a communications system.
These and other objects, features and technical advantages are achieved with a cavity slot antenna array of the present invention. The present invention provides a cavity slot antenna array for a communications system such as a wireless network. In one embodiment, the antenna array generally includes a planar array of cavity slot antenna elements for transceiving one or more (e.g., steered) signal beams. This antenna is well-suited for implementing a phased array antenna such as a phased array antenna as described in U.S. patent application. Ser. No. 09/213,640, entitled Dual Mode Switched Beam Antenna, which has been incorporated by reference into this specification. The cavity slot elements can readily be configured (e.g., through aperture tapering and reduced inter-column spacing) for generating steered beams with minimal grating and reduced side lobes. In addition, once a desired configuration has been established, the cavity slot array may be efficiently manufacturedxe2x80x94especially on a large scale or mass production basis.
In one embodiment, the present invention provides an antenna array for transmitting one or more beams in a communication system. The antenna includes a cavity slot antenna array that is adapted to be operatively connected to a beam forming module (e.g., via a plurality of signal feed lines that are connected to radiating signal probes). The antenna array has one or more cavity slot columns disposed in a predetermined relative position with respect to one another, such as adjacently fixed to one another with each of the one or more columns having at least one cavity slot antenna element for providing a radiating beam component. The combined cavity slot elements from the one or more columns define a cavity slot array for providing the one or more beams from the cavity slot beam components.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.